1. Field of the Invention
The present invention relates to an input device used to operate various electronic apparatuses.
2. Background Art
In recent years, electronic apparatuses such as portable telephones and personal computers are increasing in functionality and decreasing in size. These apparatuses are required to have an input device having a good tactile feel and reliable operation.
FIG. 6 is a partial front view of a conventional input device. As shown in FIG. 6, the input device includes ball 1 and a pair of cylindrical rollers 2A, 2B. Ball 1 is made of an insulating resin and rotatably housed in a case (unillustrated) made of an insulating resin. Cylindrical rollers 2A and 2B are made of an insulating resin and arranged perpendicular to each other in contact with the outer periphery of ball 1.
Ring magnets 3A and 3B are fixed to ends of rollers 2A and 2B, respectively. The input device further includes a pair of ring magnets 3A and 3B, in which N- and S-poles are alternately magnetized at a predetermined pitch.
The input device further includes wiring board 4 and a pair of magnetic detection elements 5A and 5B which are, for example, hall elements. Wring board 4 is provided on its upper and lower surfaces with wiring patterns (unillustrated) and disposed below ball 1. Magnetic detection elements 5A and 5B are mounted on the upper surface of wiring board 4 in such a manner as to face ring magnet 3A on roller 2A and ring magnet 3B on roller 2B, respectively, with a predetermined spacing therebetween.
The input device having the above-described structure is attached to an operating part (unillustrated) of an electronic apparatus such as a portable telephone or a personal computer in such a manner as to project the top portion of ball 1. Magnetic detection elements 5A and 5B are electrically connected to an electronic circuit (unillustrated) of the apparatus through the wiring patterns and the like.
In the above-described structure, the user rolls ball 1 with the thumb, fingers, or the palm of the hand in the right-and-left direction. The user rolls ball 1 while viewing menus including, for example, singer names and song titles, and a cursor (unillustrated) displayed on a display part (unillustrated) of the apparatus. The display part can be a liquid crystal display element or the like. This results in rotation of roller 2A in contact with ball 1 and hence, a rotation of ring magnet 3A attached to the end of roller 2A. As a result, magnetic detection element 5A opposite to ring magnet 3A detects magnetic changes in ring magnet 3A and outputs a predetermined pulse signal to the electronic circuit of the apparatus. The electronic circuit detects the direction and angle of rotation of ball 1 from the pulse signal and moves the cursor on a menu displayed on the display part of the apparatus in, for example, the right-and-left direction.
Similarly, when the user rolls ball 1 in the back-and-forth direction perpendicular to the right-and-left direction, roller 2B rotates to cause magnetic changes in ring magnet 3B. As a result, magnetic detection element 5B opposite to ring magnet 3B detects the magnetic changes in ring magnet 3B and outputs a pulse signal to the electronic circuit of the apparatus. This results in movement of the cursor or the like in, for example, the up and down direction.
When the user rolls ball 1 in an oblique direction, both rollers 2A and 2B rotate to cause magnetic changes both in ring magnets 3A and 3B. As a result, both magnetic detection elements 5A and 5B detect these magnetic changes and output two pulse signals to the electronic circuit of the apparatus. This results in movement of the cursor or the like in, for example, the right upper direction or the left lower direction.
Thus, the input device enables the user to move the cursor or the like on the display part of the apparatus in a predetermined direction by rolling ball 1 in a predetermined direction, so that the user can make a choice from the menus including, for example, singer names and song titles.
One such conventional technique related to the present invention is shown in Japanese Patent Unexamined Publication No. 2007-26026.
In the above-described conventional input device, the rotation of ball 1 results in rotation of rollers 2A and 2B arranged perpendicular to each other in contact with ball 1. This structure causes ball 1 to gather dust and dirt with time during use, and the dust and dirt accumulated between ball 1 and roller 2A or 2B can cause a scratchy or rasping feel when the user rolls ball 1.